This invention relates to seals for oven systems of the type in which articles to be treated are moved longitudinally through successive zones of the oven system.
Elongated oven systems are in common usage in the automotive and other industries to dry articles following the application of a finish coat to the articles. The coated articles are typically moved longitudinally and continuously through the oven system, through radiant and/or convection zones, to accomplish a permanent setting and curing of the finish coat. Whereas these oven systems are generally satisfactory with respect to their ability to effectively cure the finish coat, they are energy inefficient and also tend to pollute the adjacent building environment.
Specifically, large amounts of heat energy are lost out of the open ends of the oven system by heated air escaping out of the open ends into the adjacent building, and the environment of the adjacent building is polluted since the escaping air contains fumes from the drying finish coat as well as other contaminants. This movement of air out of the open ends of the oven system occurs primarily as a rollover movement in which hot, relatively thin air escapes out of the upper region of the open end and cold dense air simultaneously moves into the lower region of the open end. It is therefore desirable to seal the open ends of these elongated oven complexes to preclude energy loss and preclude contamination of the adjacent environment.
In the past, sealing has been attempted by defining sealing compartments as a prefix or suffix to the oven proper in which the articles to be treated within the oven are passed through a low, narrow tunnel having dimensions just sufficient to pass the article. While these tunnels have been partially effective, they have still allowed significant amounts of energy and contaminants to escape from the oven.
Attempts have also been made to seal the open ends of the oven by the use of forced air blown into the open ends of the oven through adjustable nozzles positioned around the periphery of the open oven ends to achieve a direct frontal assault on the air attempting to escape the oven. Whereas these frontal attack systems have been effective in preventing the escape of the hot contaminated gases from the oven, they have served to stir up the air within the oven itself with the result that the as yet uncured paint often picks up the contaminants in the stirred up air with the result that the finish coat is significantly marred.